Foreign material removal device

Abstract

Structural simplification and efficient injection state of high-pressure air from a nozzle are ensured. A foreign material removal device is provided with: a cylinder (18) into which air is caused to flow; a piston (22) which is movably supported in the cylinder and feeds the air introduced into the cylinder in a feeding direction as high-pressure air; and a nozzle (6) which injects the high-pressure air fed by the piston. Thus, the piston is moved relative to the cylinder, the high-pressure air is fed from the cylinder, and the high-pressure air is injected from the nozzle, whereby structural simplification and an efficient injection state of the high-pressure air from the nozzle can be ensured.

The invention claimed is: 
     
       1. A foreign material removal device comprising:
 a cylinder into which air is caused to flow; 
 a piston which is movably supported in the cylinder and feeds air introduced into the cylinder in a feeding direction as high-pressure air; and 
 a nozzle which injects the high-pressure air fed by the piston, wherein 
 an internal space of the cylinder has a first space and a second space which are continuous with each other in a movement direction of the piston, 
 the first space is located on closer to the nozzle than the second space, 
 a diameter of at least a portion of the second space is greater than a diameter of the first space, 
 the piston is provided with a seal portion which is brought into contact with an inner peripheral surface of the cylinder at least in the first space during movement, and 
 when the piston is moved to a bottom dead center, an entirety of the seal portion is positioned in the second space and air introduced into the second space flows from the second space toward the first space, 
 wherein the piston is moved from the bottom dead center in the feeding direction by a biasing force of a biasing spring. 
 
     
     
       2. The foreign material removal device according to  claim 1 ,
 wherein 
 an air inlet groove extending in the movement direction of the piston is formed on an outer peripheral side of the second space, and 
 the air inlet groove is formed as a portion of the second space. 
 
     
     
       3. The foreign material removal device according to  claim 2 ,
 wherein 
 a plurality of the air inlet grooves are formed so that the air inlet grooves are spaced at regular intervals in a circumferential direction of the cylinder. 
 
     
     
       4. The foreign material removal device according to  claim 1 ,
 wherein 
 the high-pressure air is injected from the nozzle toward an imaging unit of an in-vehicle camera, and 
 the nozzle is formed integrally with the in-vehicle camera.